San Francisco , California -LRB- CNN -RRB- -- Attorneys supporting the voter-approved ban on same-sex marriage in California filed a notice of appeal in the case Thursday , one day after a federal judge ruled that the measure is unconstitutional .

However , Chief U.S District Judge Vaughn Walker in San Francisco granted a temporary stay along with his ruling Wednesday , which stops his decision from taking immediate effect .

`` Proposition 8 fails to advance any rational basis in singling out gay men and lesbians for denial of a marriage license . Indeed , the evidence shows Proposition 8 does nothing more than enshrine in the California Constitution the notion that opposite-sex couples are superior to same-sex couples , '' Walker , who was appointed to the federal bench by former President Ronald Reagan , wrote in his opinion .

Supporters of Proposition 8 argued , prior to Walker 's ruling , that same-sex marriages would be performed soon after his decision and could be complicated by rulings and appeals farther down the legal road .

The judge 's decision striking down the ban handed supporters of gay rights a major victory in a case that both sides say is sure to wind up before the U.S. Supreme Court .

The case will be appealed to the 9th Circuit U.S. Court of Appeals . Paul Callan , a former New York prosecutor and criminal defense attorney , said he believes Walker 's decision is likely to be upheld there , saying the appeals court `` is a very liberal court which is favorable on these issues . ''

Walker 's 136-page decision does a good job in laying out a compelling case for the unconstitutionality of the proposition , Callan said . `` He 's looking ... to the appellate process , which is going all the way to the Supreme Court . ''

But , he said , the nation 's highest court typically handles big social questions like this one slowly , allowing state and lower federal courts to issue decisions . `` And they kind of let it percolate in the lower courts , '' Callan said .

Opponents of same-sex marriage have said their best bet lies with higher courts .

`` The court 's disregard for the historical purposes of marriage would require California to embark on a novel experiment with the fundamental institution of marriage , '' said Charles Cooper , lead counsel for Proposition 8 supporters , in a statement .

He said Walker 's decision treats children as a `` mere afterthought when it comes to marriage ... And the court also found that there is no benefit whatsoever for a child to be raised by its own biological parents .

`` Fortunately , the Constitution does not require the people to substitute the social science musings of gay rights activists for common sense , '' Cooper said . `` This decision will not stand . ''

Callan said he does n't expect the Supreme Court to enter the fray immediately .

`` I think it 's probably going to be another couple of years . A lot of cases will be decided by the lower courts , and then they 'll move in and make the big decision as to whether it 's legal or not , gay marriage , '' he said .

The proposition defines marriage as a union between a man and a woman . At stake in the trial was whether the ban violates same-sex couples ' rights to equal protection and due process , as protected by the U.S. Constitution .

Same-sex marriage is currently legal in five U.S. states -- Massachusetts , Connecticut , Vermont , Iowa and New Hampshire -- and in the District of Columbia , while civil unions are permitted in New Jersey .

Walker pointed out in his ruling , `` race restrictions on marital partners were once common in most states but are now seen as archaic , shameful or even bizarre . Gender no longer forms an essential part of marriage ; marriage under law is a union of equals . ''

Elated supporters of same-sex marriage gathered to celebrate the judge 's opinion in the Castro district of San Francisco .

After speeches and songs , they began a march to City Hall .

People waved rainbow flags and U.S. flags , and carried signs that read , `` We all deserve the freedom to marry , '' and `` Separate is Unequal . ''

Similar rallies unfolded in cities across California -- including Los Angeles and San Diego .

`` For our entire lives , our government and the law have treated us as unequal . This decision to ensure that our constitutional rights are as protected as everyone else 's makes us incredibly proud of our country , '' said Kristin Perry , a plaintiff in the case along with Sandy Stier . Jeffrey Zarrillo and Paul Katami are the other couple at the heart of the case .

Many Americans , however , still oppose same-sex marriage . In a national survey , conducted by Gallup in May , 53 percent of respondents said such marriages should not be recognized by law , while 44 percent said they should .

Proposition 8 is part of a long line of seesaw rulings , court cases , debates and protests over the controversial issue . It passed in California with some 52 percent of the vote in November 2008 .

`` Big surprise ! We expected nothing different from Judge Vaughn Walker , after the biased way he conducted this trial , '' said Brian Brown , president of the National Organization for Marriage . `` With a stroke of his pen , Judge Walker has overruled the votes and values of 7 million Californians who voted for marriage as one man and one woman . ''

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NEW : A notice of appeal has been filed in the case

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A California judge ruled the state 's ban on same-sex marriage is unconstitutional

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The decision is a major victory for proponents of same-sex marriage

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The case is expected to ultimately land at the U.S. Supreme Court